What makes a high school great? Its average SAT scores? The number of National Merit scholars it produces? How many of its students are admitted to Ivy League colleges?

In December, The Post will publish its eighth annual Challenge Index, a ranking of area public high schools based on student participation in college-level courses and tests. I have been preparing these rankings for The Post, and similar national lists for Newsweek, since 1998. I think they are a useful way to identify which schools are trying hardest to prepare their students, particularly average and below-average students, for college. But it is not enough.

Parents and students yearn for a way to figure out which schools do best in less tangible ways. Which has a fabulous principal, or a veteran teaching staff, or a great drama program, or counselors ready to go the distance, or a tradition of making sure no kid falls through the cracks? Which schools are most likely to meet the needs of minority students or those with disabilities?

There is no easy way to calculate those things. So the Magazine is going to try an admittedly impractical and unscientific assessment tool. We want you to tell us which high schools you think are best, and why.

We call this the Back Fence Survey because that is the way information about schools is usually transmitted, from neighbor to neighbor. We are looking for the best local high schools in three categories: public schools, private schools and schools that do a great job with minorities or kids who don't speak much English yet or who come from disadvantaged backgrounds. Please send your nominations to my e-mail address, mathewsj@washpost.com, or my snail-mail address, 526 King St., suite 515, Alexandria, Va., 22314. You may nominate up to 10 schools in each category.

The more concrete details and anecdotal evidence you can provide for each of your choices, the better. Those who participate should explain not only what they like about the schools on their list but how they happen to know about them. The source of your information can range from "I have a friend who works there" or "I used to teach there" to "Three of my kids have attended" or "Everyone at my gym raves about it."

Please be sure to disclose any direct personal connection to any of the schools -- as parent, student or staffer. Don't vote just for schools that your children attend, or we will suspect a campaign to stuff the ballot box. We also will need your name, phone number and/or e-mail address.

We hope to hear about any schools in the District, Northern Virginia or the Maryland suburbs, including Montgomery, Prince George's, Frederick, Howard, Anne Arundel, Charles, Calvert and St. Mary's counties.

This is, in a way, a reputational survey, similar to the one that U.S. News & World Report sends to higher education administrators and gives the greatest weight to in its rankings of "America's Best Colleges." But we will also gather statistical data on the schools you nominate, such as SAT scores, Advanced Placement or International Baccalaureate participation and college acceptance rates.

We want to help break down barriers that make it difficult for families to find the schools they are looking for. Public schools, for instance, provide much useful information about themselves. The law requires it. But private schools are stingy with standardized data and in many cases resist efforts to quantify what they are doing.

Finding a school with the right atmosphere for a particular child preoccupies many Washington area families. The idea of a list of schools that do a great job with minorities was inspired by an e-mail to me from Spencer Overton, a law professor at George Washington University, who likes to plan ahead. His son is 2 years old, but Overton wants to start looking now for the private or public high schools that "have the largest percentage of African Americans doing well, both in terms of raw numbers and compared to students of other ethnic backgrounds."

Please ask everyone you know who is knowledgeable about schools to participate. We will report the results next spring in what promises to be a very lively issue of the Magazine's Education Review.